Common Electrode Slit Design for LCD Gate Field Shielding
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Solution Overview
Problem
In liquid crystal display devices using transverse electric fields, the counter-electrode is prone to electrification due to the gate potential, leading to unwanted vertical electric fields and potential light leakage or flicker, which degrades display quality.
Innovation Solution
A liquid crystal display device structure where the common electrode is disposed on the array substrate to face the pixel electrode and gate line, with slits facing the pixel electrode, and optionally formed over the entire display area to shield the electric field generated by the gate potential, and trenches between the pixel electrode and source line to prevent electrical coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the common electrode is disposed to face the gate line in transverse electric field mode, then the electric field shielding effect is improved, but the device structure becomes more complex
Solution Approach 1:
The common electrode is segmented into multiple regions: a first region facing the pixel electrode and a second region facing the gate line. This segmentation allows different portions of the common electrode to serve different functions - one for pixel control and another for shielding the gate line's electric field, thereby resolving the contradiction between improving shielding effect and maintaining structural simplicity
Solution Approach 2:
The common electrode is designed to perform multiple functions simultaneously: it serves as the common electrode for pixel control and also acts as an electric field shield for the gate line. This multi-functionality eliminates the need for separate shielding structures, improving the shielding effect while avoiding increased device complexity
2Reliability
If the distance between pixel electrode and source line is increased to prevent electrical coupling, then the electrical coupling is reduced, but the aperture ratio decreases
Solution Approach 1:
A trench structure is introduced as an intermediary element between the pixel electrode and source line. This trench acts as an electrical isolation barrier that prevents unwanted electrical coupling without requiring increased spacing between the electrodes, thereby maintaining both electrical reliability and high aperture ratio
Solution Approach 2:
Instead of solving the electrical coupling problem by increasing horizontal distance between pixel electrode and source line, the solution moves to the vertical dimension by introducing a trench structure. This dimensional shift allows electrical isolation to be achieved through depth rather than width, preserving the aperture ratio while preventing coupling
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration suppresses electrification of the black matrix on the counter-substrate, prevents light leakage, and enhances display quality by maintaining a desired transverse electric field and increasing aperture ratio, while avoiding the need to increase the distance between pixel and source lines.
Implementation Method 1
the common electrode is disposed on the array substrate to face the pixel electrode and gate line, with slits facing the pixel electrode, and optionally formed over the entire display area to shield the electric field generated by the gate potential
Implementation Method 2
The modulation ratio of light passing through the liquid crystal layer is controlled by an electric field between a pixel electrode and a common electrode, thereby displaying an image
Implementation Method 3
liquid crystal molecules are switched by generating a transverse electric field that is substantially parallel to the major surface of the array substrate
Data Source
AI summary
An array substrate of a liquid crystal display device includes an insulating substrate, a gate line extending in a first direction on the insulating substrate, a first insulation film which is disposed to cover the gate line, pixel electrodes which are disposed on the first insulation film in respective pixels, a source line which is disposed on the first insulation film and extends between the pixel electrodes along a second direction, a second insulation film which is disposed to cover the pixel electrode and the source line, and a common electrode which is disposed on the second insulation film in a manner to face the pixel electrode of each of the pixels and to face the gate line, and includes a slit which is opposed to the pixel electrode.